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Saturday, 30 April 2016

Gun design is driven by the desire to be at least half a step ahead of its opposition. The creators of tank armour aim to provide tank crews with maximum possible protection from all existing weapons, and gun designers aim to create a gun that would penetrate the armour of any modern tank. In the spring of 1941, work on a new 107 mm anti-tank gun began in the Soviet Union, a gun that would not see a worthy adversary for several years. Both these guns and their likely enemies were built in metal, but neither one ended upon the battlefield.

Shooting at Shadows
At the start of 1941, Soviet anti-tank artillery evolved simultaneously in several directions. The most promising weapon was the 57 mm F-31, later indexed ZiS-2. This gun was developed at factory #92 under the direction of V.G. Grabin. In parallel, a "powerful 76 mm AT gun on the USV base" was developed, with the factory designation F-26. It was plagued with difficulties. Due to problems with the recoil brake, the gun was redesigned several times. Finally, in early January of 1941, under Grabin's initiative, an 85 mm anti-tank gun was also developed. It was based on the mount of the experimental 95 mm F-25 divisional gun with lengthened trails. In January, it fired 225 shots.

On March 11th, 1941, the chief of the Red Army General Staff Intelligence Directorate, Lieutenant-General F.I. Golikov, prepared a special report "On the direction of development of the armed forces of Germany and changes in its status". According to this document, German industry began constructing three new types of tanks. The most powerful one, called "Type VII" allegedly weighed 90 tons and was armed with a 105 mm gun. The military treated this information very seriously. The T-150, which was supposed to enter production as the KV-3, was cancelled. Instead, a new vehicle was developed on the basis of the KV-220. The new KV-3 would have a 107 mm gun, have armour about 120 mm thick, and weigh 67-68 tons. In addition, KV-4 and KV-5 tanks were developed in parallel.

Tanks weren't the end of it. By April 18th, 1941, a Council of Commissars decree titled "On tank armament, new anti-tank gun, artillery SPGs, and armour piercing ammunition" was prepared. The sixth point of the decree is most relevant:

"6. On the powerful 107 mm corps gun.

Order the NKV to develop and produce at factories #172 and #92 experimental guns with a 107 mm barrel with the muzzle velocity of 1100 m/s on the mount of the 152 mm mod. 1937 gun-howitzer mount.

Due date for delivery of experimental prototypes to the NKO: July 1st, 1941

By the same due date, produce a tank destroyer with a 107 mm gun of the aforementioned ballistics. The NKTM must build this tank destroyer on a lengthened KV-4 chassis with 60 mm of armour.
The NKB must develop and produce by that date 3000 armour piercing shells with tracer, phlegmatizer, and decopperer in the propellant."

The tank destroyer mentioned in the decree was to be developed in parallel with the SU-B-13 and "212" SPG. According to project documentation, development of the SU-B-13 began, a project was drafted, tactical-technical requirements were made, and the project stalled. The production of the 212 SPG ended during construction of the hull. Unlike these two, the project of the tank destroyer did not even reach the tactical-technical requirements stage. However, the "powerful 107 mm corps gun" made it further.

Preliminary calculations showed that the new powerful gun with a muzzle velocity of 1100 m/s would penetrate 188 mm of armour at a 30 degree angle at 1000 m. By early May, the characteristics changed. According to calculations for the 107 mm anti-tank gun, the muzzle velocity was reduced to 1020 m/s and the length of the barrel would be about 60 calibers. Even this data was not final.

Meanwhile, Grabin displayed his initiative and began developing a lighter alternative for the ZiS-24. This gun, indexed ZiS-23, used the mount from the 107 mm M-60 divisional gun, and its muzzle velocity would be 1150 m/s with a 70 caliber barrel.

The development of tactical-technical requirements for the new guns dragged on. The GAU Artillery Committee reviewed them only on May 22nd, 1941. According to the characteristics, the velocity of the 18.8 kg 107 mm armour piercing shell was kept at 1020 m/s and the penetration was decreased to 160 mm at 30 degrees. The barrel length was limited to 70 calibers. The rate of fire was set at 10 RPM with one piece rounds. The mount from the 152 mm ML-20 would be used as much as possible during development, including the sight. In addition to its AT duties, the gun would act as a corps gun, which is why it would also have an 18.8 kg HE shell fired at 730 m/s.

Draft project of the 107 mm M-75 antitank gun.

On the same day, requirements for a "special purpose 85 mm anti-tank gun" were approved. The gun would also serve as a divisional gun, and have a 9.2 kg 800 m/s HE shell. As for the AP shell, it was fired at 1150 m/s and weighed 10.5 kg, letting it penetrate 160 mm of armour at 1000 m at a 30 degree angle. The requirements included the use of the M-60 107 mm gun mount. Changes would be minimal and would include the gun shield.

Heavyweight Competitor

Until early June of 1941, design of high power AT guns proceeded only at factory #92, even though the decree mentioned two factories. This can be explained by Grabin's initiative, which was noticed at the top. Either way, factory #172 was too busy: it still had a large order for howitzer artillery and Supreme Command Reserve artillery to complete.

The requirements kept changing throughout the end of May and the beginning of June. The final variant was only sent to the factories on June 7th. By that time, factory #172 finally began the development of its own 107 mm gun. The latest changes put the factory in a difficult position, as they included the use of a mechanical rammer and variable rifling. In a letter to the chair of the Artillery Committee, Major-General Hohlov, acting director Kudryavtsev wrote that the design bureau would design a gun without these features. According to the bureau, the rate of fire of 10 RPM was attainable without a mechanical rammer. The gun designed at factory #172 was indexed M-75. According to preliminary calculations, its muzzle velocity was 1020 m/s and its penetration matched the requirements.

The gun shield that would be installed on all high power anti-tank guns.

Interestingly enough, development of an 85 mm gun began in Molotov (modern day Perm), and only fragmented information survives to this day. Information on it first comes in up mid June of 1941. Correspondence between factory #172 and the People's Commissariat of Ammunition reveals that not enough test rounds were produced for the ZiS-23 to also test the factory #172 gun. As a result, another 300 shells would have to be made: 50 by July 5th and the remaining 250 by July 15th. Further letters reveal the index of this gun: M-76. The letters also state that factory #172 received permission from the state to build a prototype.

No tactical-technical characteristics for the M-76 were found. As for its competitor, the ZiS-23, its characteristics were finally confirmed in early July of 1941. To develop a muzzle velocity of 1150 m/s, the gun barrel was 96.8 calibers (8228 mm) long. The ZiS-24 also did not meet its barrel length restrictions. According to the final characteristics, the overall length of its barrel was 73.5 calibers, or 7843 mm.

The characteristics document dated July 4th, 1941, also mentions that factory #92's guns were finished and were currently at the stage of prototype assembly. Whether or not assembly was ever completed is not known. By June 31st, 1941, both guns were still being designed. Factory #92 had to send off two ZiS-23 prototypes (priority of the ZiS-24 was reduced) by August 15th. This did not happen, and furthermore, both guns are absent from a report on factory #92's experimental work. No additional information appears in subsequent documents. It is very likely that the ZiS-23 and ZiS-24 were never built.

Unexpectedly, a third competitor entered the race. On July 7th, 1941, a letter from Sverdlovsk arrived, addressed to the chief of the Orders and Production of Land-based Artillery Directorate (UVNA). The authors of the letter were the chief engineer of the Ural Heavy Machinebuilding Factory (UZTM) and F.F. Petrov (one of the creators of the ML-20 gun). In the letter, they described a draft of an anti-tank gun indexed UML-20.

Draft project of a 107 mm UML-20 anti-tank gun, July 1941.

The main feature of the project was that the gun was as unified as possible with existing guns, the ML-20 and A-19. The screw breech lock and barrel case were taken from the A-19. The breech and mount came from the ML-20. The A-19 also donated its shell casing. The possibility of using M-60 shells was mentioned, but it was not known if the shell would survive the higher pressure. The muzzle velocity was estimated at 1050 m/s with a barrel length of 59.5 calibers. In order to compensate for the altered center of mass, the barrel was extended by 235 mm.

Calculations for the UML-20 barrel. Unlike this gun, documentation for the ZiS-23 and ZiS-24 did not survive to this day.

UZTM's proposal was very reasonable. Thanks to the use of existing parts, development and, most importantly, production could have been completed quickly. However, the UML-20 project did not move past the design proposal stage.

In the end, the only high power anti-tank gun that reached the trials stage was S.N. Dernov's M-75.

Without a Worthy Target

Technical documentation for the 107 mm M-75 anti-tank gun was prepared by factory #172 by the end of June of 1941. The start of the Great Patriotic War did not influence its development. Unlike work on the KV-3, KV-4, and KV-5 tanks, no one cancelled work on the high power gun. Factory #172 began production of two prototypes in early July, and factory trials began by the end of the month. Muzzle velocities between 1017 m/s and 1047 m/s were recorded, which met requirements. The driving bands were not torn. Penetrations in the plate were in the form of a circle, meaning that the shells were stable in flight. The biggest problem during trials was the work of the semi-automatic mechanism. This was caused by the materials that were used to make the breech and breechblock.

M-75 on trials, October 1941.

On July 15th, a technical project was sent to UVNA chief, Military Engineer 1st Grade Komarov, developed in parallel with the production of prototypes. Overall, the gun met requirements. Its muzzle velocity was 1020 m/s, the barrel was 70.5 calibers long (7550 mm), and the design used the ML-20 mount. Nevertheless, the project was met with the following response:

"Instead of installing the new 107 mm barrel on the ML-20 mount, the factory performed an unfortunate "modernization" of the mount."

A more complete version of this appraisal was sent to factory #172 on July 28th, 1941, signed by GAU chief General-Colonel Yakovlev.

The same gun in firing position.

This reaction was caused by changes made at factory #172 to the design of the mount. Instead of the stock system to move the barrel from travel to firing position, a pulley was used, like the M-60. Aside from the change, GAU made a reasonable complaint about whether or not the addition would increase the speed at which the barrel could be transferred to and from the firing position. The designers of the M-75 also changed the recoil system and designed an almost completely new limber. In the conditions of war when German heavy tanks were expected any day, this was deemed unacceptable. Mass production M-75 had to be built on an ML-20 mount with a stock limber.

Despite a requirement to use the ML-20 mount as much as possible, the M-75 prototypes had may changes in their design.

Further trials of the M-75 were performed at the Ural Artillery Proving Grounds (today the Nizhniy Tagil Metals Research Institute, NTIIM). The trials program was approved on August 16th, 1931. The robustness of the system, its ballistics, and penetration were tested. Gun #1 had a barrel #4 with 25 caliber rifling and gun #2 had a barrel #7 with 32 caliber rifling. Barrel #5 was shipped with the guns, also with 32 caliber rifling.

Gun in travel position. Instead of the stock system for moving the barrel from travel to firing position, a pulley like on the M-60 was used.

Documentation for the gun was delivered on August 28th, but trials only began one month later, on September 29th. The first stage of the trials was disassembly and reassembly, during which the guns switched barrels. Trials were complicated by a lack of equipment at the Ural proving grounds for various necessary work.

The first shots were fired only on October 5th from gun #1. On October 16th, after 105 shots, trials were stopped due to a suggestion from factory #172. This was caused by the need to make a new breechblock and several other components. Trials resumed on November 3rd. After 402 shots, barrel #5 was replaced with barrel #4 due to significant wear of the rifling. Firing trials ended on December 11th, but due to the busyness of the proving grounds staff with other guns, the report was only composed on January 2nd, 1942.

Gun in firing mode, from the front.

The results of the trials were not encouraging. Fist, the lifespan of one barrel was estimated at 250-300 shots, which was not enough. Second, there were serious problems with penetration. The gun penetrated 152 mm of armour, but only at 100 meters. No attempt was made to fire at one kilometer due to the weakness of the shell hulls. This was a problem with many Soviet shells already in production, and it was not solved immediately. The real rate of fire of the gun was 5-6 RPM. There were significant problems with extraction. The M-75 failed trials.

Shells for the 107 mm M-75 gun.

Factory #172 had the potential to improve the M-75. Many guns, including anti-tank guns, showed these drawbacks. Trials showed what had to be corrected. Also, as mentioned above, the Ural proving grounds were not properly equipped for trials, and many problems could easily be solved at the factory. Nevertheless, on April 22nd, 1942, a decree was issued cancelling work on high powered anti-tank guns.

"Since the experience of modern war did not confirm the need for such guns to fight tanks, further work on the M-75 gun and its ammunition is considered unreasonable. Reporting on the above, I ask for your permission to cease all work on the 107 mm M-75 gun and similar work on 85 mm and 107 mm ZiS-23 and ZiS-24 guns at Order of Lenin factory #92.

107 mm shells could penetrate armour, but cracked on impact.

The People's Commissar of Armament, Colonel-General Volkov, did not know that right when he signed that letter, Ferdinand Porsche's design bureau began work on the super-heavy tank that super-powered anti-tank guns were made for. Of course, neither the VK 100.01 nor the Maus ever reached the front lines. Nevertheless, the gun cropped up once more in 1943.

M-75 gun #1 on display at the future site of the Armed Forces Museum of the Republic of Kazakhstan, in Astana.

In July of 1943, at Ponyri, another brainchild of Porsche K.G. entered battle: the Ferdinand SPG. Its appearance was treated seriously by the Red Army. The M-75 appeared once more in the list of work on tank, anti-tank and self-propelled artillery dated September 15th, 1943. One of the reasons that the project was buried in 1942 was the use of the ML-20 mount. The idea of a tank destroyer with the M-75 had another chance at life two years after it was first discarded in 1941, especially now since it had a worthy target.

The return to 107 mm artillery was brief. In the same letter that mentioned the M-75, Major-General Hohlov proposed discarding a number of projects, replacing them with a much more promising 122 mm gun with the muzzle velocity of 1000 m/s.

There is a simple rule: cheap, good, fast, pick two. AT guns are long and expensive. What do you do when fighting enemy tanks with a log is foreseen in the near future?

British Ersatz Grenade Launchers

When the British were expecting the Germans to invade the British Isles, Major Harry Horthover came up with the so called Northover Projector. This solution was cheap indeed: only 10 Pounds Sterling apiece.

This weapon consisted of a pipe 2.5" (about 80 mm) in diameter with a simple screw breech, set up on a tripod. The loading process consisted of loading a round, then a pouch of black powder. The grenade launcher could fire a rifle grenade or grenade #76, a vessel filled with incendiary fluid that the British prepared 6 million of by the end of the summer of 1941.

What can be said about the Northover Projector? First, separate loading is a slow process. Second, black powder reveals the gun. Finally, hitting something with the weapon at a range of over 140 meters was almost impossible. In a real battle, it was doubtful that this wonder-weapon could fire more than once, and yet 19,000 Northover Projectors came off the assembly line.

Nortover was only a Major, but even the higher ranks were bitten by the invention bug. For example, Lieutenant Colonel Stuart Blacker proposed a bombard of his design which he was working on since before WWII. In his opinion, the bombard combined the best features of the 40 mm AT gun and 81 mm mortar. His invention was a spigot mortar (the caliber of the round was bigger than the caliber of the barrel) 10 kilogram shells. It could fire from either a stand or a concrete foundation. The range of this gun was miserly: only 50 meters.

The British build the first Blacker Bombards in the end of 1941 when it was already obvious that the Wehrmacht was bogged down fighting the Soviets and that German landing craft are unlikely to cross the Channel. However, the inertia of the war machine resulted in about 22,000 bombards being built. Looking at this Blacker Bombard and the Northover Projector once might wonder if the metal would have gone to better use in the production of a few hundred real AT guns.

By the way, the British did not limit themselves to these two weapons. Another design was proposed by Major William Smith. His design stood out due to its transportation method: the grenade launcher was wheeled around on a two wheeled cart, equipped with a shield. In combat, the grenade launcher was tipped on the side. In order to make it clear to the Home Guard which end was up, one wheel was made concave and the other convex. The range of "Smith's Gun" was about 150 meters. 3000 units were build by 1943. The British militia did not like this weapon: it was too heavy to push around. Towing it was forbidden as it might break.

Ampulomet - A Picky Pipe on Wheels
Soviet engineers were also tempted by the cheap and quick. In the 1930s, 125 mm glass and later tin ampoules filled with incendiary fluid were developed for dropping from aircraft. It is unknown who decided to bring this weapon down from the skies. It is only known that the development of the ampulomet began at the Moscow Kirov factory #145.

The result was a pipe on wheels, officially accepted into service under the index "125 mm ampulomet mod. 1941". The ampoule was projected by a 12 gauge blank.

Initially, the ampulomet was not considered an anti-tank weapon, but in 1941 the situation demanded that everything that could theoretically destroy a tank must fire at them. The impact from a 125 mm ball of flame was considered more impressive than a lesser sized bottle of incendiary fluid.

However, "must be" and "is" are two different things. Usually when historians discuss the effectiveness of ampulomets in anti-tank roles, they recall a story from D. Lelyushenko's 30th Army in early December of 1941. An engineer arrived in one of its battalions with 20 ampulomets. Lelyushenko decided to personally try out this novelty. Lelyushenko replied to the engineer's description of how to load the ampulomet: "too complex and too long, the German tanks will not wait".

On the first shot, the ampoule burst in the barrel and the ampulomet burned up. Lelyushenko demanded a second attempt, and the situation repeated itself. The enraged general prohibited the use of this unsafe weapon by his troops and had the remaining ones crushed with a tank. It is hard to say how accurate this story is, but Dmitriy Danilovich Lelyushenko had a rather difficult character.

Lelyushenko was not the only one to encounter the problem of premature bursting. In April of 1942, the 370th Infantry Division attempted to use ampulomets. Use in combat did not pan out, as the soldiers were unable to get within the required 100-150 meters of the enemy, and the results of training exercises were not encouraging:

"

Out of the 12-15 burst ampoules at training exercises in the 307th division, 8 did not ignite.

10-15% ampoules fired at exercises at the HQ burst in the barrel.

Out of 52 ampoules tested, taken from various crates stored at warehouse #1801, 19 burst in the barrel, which is a failure rate of 36.5%.

The cause of the premature bursting is due to low quality manufacturing: ampoules are not properly welded and were presumably not checked for robustness when produced. Without firing, it is impossible to determine a faulty ampoule visually."

It is not difficult to understand the soldiers that did not want to go to battle with such a weapon. The attempt at a fast and cheap solution harmed the quality of the weapon. Yes, it was used on several parts of the front, but the ampulomet was not destined to end up among the weapons of victory. It remained a symbol from difficult times when even a pipe on wheels had to be taken into battle.

Thursday, 28 April 2016

As crazy as the final vehicle turned out, the Maus had the potential to be a whole lot crazier. Compared to the idea of slapping a mini-turret on top of the existing one, the idea of a cupola with an AA machinegun seems downright reasonable. I mean, once you get over the incredibly limited vertical traverse angles that would have made it work quite poorly against aircraft.

On August 29th, 1941, the commission consisting of chair Intendant 3rd Grade comrade M.V. Kudryavtsev and members Military Technician 1st Grade comrade F.A. Olkhov and Military Technician 2nd Grade comrade A.P. Pavlov performed an inspection of a KV-1 tank with a 76 mm ZiS-5 gun sent to the ANIOP at the Gorohovets Artillery Proving Grounds from factory #92 (Gorkiy) for the purpose of undergoing proving grounds trials on request of Interim Chair of the Artillery committee #281347s issued on August 22nd, 1941. The following items arrived:

In carrying out order #550s issued by the People's Commissar of Tank Production on September 17th of this year, we send the following materials for approval:

Assembly blueprints of a reinforced gun mantlet mount for the D-5 gun in the SU-85 SPG. The blueprints are sent simultaneously with the order to begin production. The reinforced gun mantlet mount will enter mass production starting in October of this year.

A proposal of a commander's cupola for the SU-85 in two variants:

First variant: installation of a cupola on the existing SU-85 hull with minimal changes (cutting a hole in the roof and side, a special cap, etc). In this variant, the commander's cupola could be quickly installed in production.

Second variant: installation of a cupola widened to the width of the tracks while maintaining the front plate. This variant was developed by UralMash factory only as per the conditions of order #550s."

You're all familiar with variant #1, but variant #2 was rather more interesting.

Monday, 25 April 2016

The effects of "big cats" being shot up by large caliber Soviet shells are wellknown, but naturally every other Allied nation was willing to have a go themselves. Three British reports surfaced on Google Photos with just that. Unfortunately, they don't test as many tank guns as the Soviets do, settling for only the 6-pdr, 17-pdr, and occasionally the M3 75 mm gun on the Sherman, but they also test ground attack aircraft autocannons, 7.7 mm bullets, 25-pdr HE shells, and the humble PIAT. Despite the smaller caliber of the weapons, the German armour spalls, splinters, and shatters almost as well as during the Soviet trials. The conclusions are, well, predictable.

Go ahead and flip through them to see the power of Britain's rather underrated guns in action. Unfortunately, conclusions made about the Tiger II are based on calculations only.

Sunday, 24 April 2016

In April of 1945, Soviet Marshal Radion Malinovskiy was faced with new battles in Czechoslovakia. The Red Army already knocked their enemy out of Bratislava and now had to develop its success to take Brno.

The Brno industrial center was of great significance for Germany since the occupation in 1939. Brno was the home to Zbrojovka Brno, one of the largest small arms manufacturer in Europe, as well as a Skoda factory.

From the Flank
After the Germans lost the Moravian industrial zone (also in Czechoslovakia) and a rapidly diminishing scrap was left of the "thousand year reich", the Brno industrial area was of vital importance to the Germans. The Soviets also needed it, as it opened up the road to Prague.

The taking of Brno had to be a combined operation. Mobile units would encircle the city. For this, Malinovskiy's Front was given the 6th Guards Tank Army, freed up after taking Vienna, in addition to General Issa Aleksandrovich Pliev's mechanized cavalry group.

Andrei Grigoryevich Kravchenko's army travelled a long way in the Vienna Offensive Operation, from Hungarian rivers and channels to the ancient streets of the Austrian capital. This path was not easy. For example, the 46th Guards Tank Brigade had 65 new M4A2 Sherman tanks in February of 1945. By the time the brigade was breaking through at Brno on April 23rd, it only had 13 tanks left. The small number of tanks was partially compensated with SPGs from the 51st and 208th SPG brigades, also beat up. In total, they gathered up three SU-122s, fifteen SU-76es, and ten SU-100s.

The first serious battle took place at Trzhevomyslitse. The Germans were seriously prepared: the village was occupied by tanks, SPGs, artillery and infantry. The report of the 46th brigade laconically reads: "it was impossible to take the village with a frontal attack". Soviet forces attempted to distract the Germans with SPG fire while tanks came around the flank. The maneuver was successful, and the tanks reached the outskirts of the village. The village with a complicated name was taken, at the cost of two burned up tanks. SU-100 gunners reported two destroyed Panthers and one Ferdinand.

There was a canal right after the village, and the Germans blew up all the bridges across it during their retreat. However, this did not hold the Soviets for long. By 03:00 on April 24th, engineers built a temporary bridge and the tanks moved forward once more. The next German stronghold was at Tuřany and the nearby height 228. First from tanks and artillery completely covered the road and the two lead tanks were knocked out. There was no possibility to advance, but this was 1945, and Soviet tanks didn't attack head on unless it was absolutely necessary. The tanks moved around, through Dvorksa village, and hit Tuřany from the side where they weren't expected. The battle didn't last long. the Germans ran before midnight, leaving behind nine tanks and SPGs (five of which were fully functional) and a variety of other vehicles.

Main Assault
For several hours, Soviet vehicles were stocking up on fuel and ammunition. There was no time to sleep; tanks moved out at 03:00. One German ambush was destroyed without losses and by noon our units reached Slatina, the last line of defense before Brno. It was impossible to move further: an advance party that was sent out lost three Shermans to a German ambush. Reconnaissance on foot didn't turn up much. "There was no possibility to move up, and no way around." the reports read, dryly. Soon, the Germans counterattacked, trying to take Slatina back from the Red Army, but came under fire from the SU-100s. The SPG gunners claimed two Ferdinands and as many StuGs.

The enemy defenses had to be softened up. Forward units called in artillery and aircraft support. On April 25th, shells and bombs pounded the German defenses into the dirt, after which the tanks went on the offensive again. Even now, reports came from the battlefield on "infantry battalions rose up to attack time after time, with no effect... the enemy staunchly defends each street, each block, each house".

By the evenings, the Soviet forces had a foothold in the outskirts of Brno. After that, it was the typical street fighting again: assault groups, with an infantry company, a tank platoon, a battery of SPGs and a platoon of 76 mm guns. Battles raged on with no rest. By dawn on April 26th, tanks reached the center of the city, having run out of ammunition. Thankfully, the Germans had no opportunity for a counterattack: Pliev's mechanized cavalry was attacking the city from the south. By the evening, the city fell.

The Bratislava-Brno operation was not over. Soviet forces moved on to meet their neighbouring Front, surrounding the Germans at Olomouc and making their way to Prague.

Saturday, 23 April 2016

The Battle of Leningrad became a proving grounds for new weapons. From the middle of 1941 to the summer of 1944, the battlefield here saw the newest and most extraordinary creations from both side of the front line. Finding armoured vehicles here was most surprising, as the conditions did not make it easy to use tanks and SPGs. One of the most unusual vehicles that could be found here was a German 105 mm SPG on the chassis of a British light tank.

British tank, German howitzer
The creation of these interesting SPGs is covered in a number of works in both the German and English languages. As a brief reminder, many trophies were captured by the Germans after the fall of France in the summer of 1940. Among them were many armoured vehicles. One of the, the British Light Tank MkVI, served as the chassis for a German 105 mm mod. 1916 howitzer. The author of this project was Captain Bekker, commander of 12th battery, 227th Artillery Regiment, 227th Infantry Division.

The result was a lightly armoured vehicle with a casemate, open from the top and partially from the rear. The crew consisted of 4 men. The thickness of the front armour was 22 mm, 15 mm in the sides. The vehicle turned out very compact, especially when you consider the caliber of the gun. The length of the vehicle was under 4 meters, while the height was only 2 meters. The mass was less than 6.5 tons. The 88 hp engine allowed it to develop a very impressive speed: 40-50 kph on roads.

The maxium range of this improvised SPG was 9200 m. As a bonus, the gun could use ammunition from the most common weapon of German artillery regiments: the 105 mm leFH 18.

Six tanks were converted into these SPGs and were put through trials. All that was left was to test them in battle. The vehicles were formed into an extra 15th battery in the artillery regiment of the 227th division, with three platoons of two SPGs each. The battery was also equipped with munitions carriers. In documents, it was occasionally referred to as an assault battery. Even though using these SPGs as assault guns was not strictly correct, their combat history is long and varied.

Use in combat, 1941

For a while, the 227th division remained in France, but Army Group North urgently needed reserves by fall. The division was transferred to the Soviet north, where it was included in the 1st Army Corps. The 227th Division replaced elements of the 39th Motorized Corps in the forests south of Ladoga.

Almost instantly, the division ended up in the center of battle. The Soviet 54th Army desperately tried to penetrate the blockade. At the same time, German command was planning an offensive against Volkhovstroy. For the time being, the 227th division was defending.

On October 15th, 1941, the 15th battery took up positions in three places where tanks could appear, one platoon each. Several days were spent shooting at the enemy. The Germans were preparing for an offensive, and two platoons were transferred to the neighbouring 254th Infantry Division. They returned only after the 54th Army's offensive began on October 20th.

On October 23rd and 24th, the SPGs fought actively, firing over 200 rounds. They were also used as infantry support weapons. As a result, the battery suffered its first casualties: 4 men, including Bekker, were wounded.

On November 15th, another attempt to use the SPGs as assault guns was made in support of the unsuccessful assault by the 223rd Infantry Division. The battery lost three men killed, and one SPG was left in no man's land. It was only recovered after three days. Second and third platoons had a similar experience. The vehicles showed themselves to be well designed and reliable.

Out of the battery's three platoons, the first was the most active. Starting in late October, it supported the 11th Infantry Division as it attacked towards Pogostye and Volkhov. SPGs from the platoon fought alongside infantry, to the point of having to use hand grenades and the crew's personal weapons. On November 11th, the platoon fought Soviet tanks near Khotovskaya Gorka village. In this battle, one vehicle was hit 16 times, but its armour was never penetrated. This episode is confirmed by Soviet sources.

The village was defended by elements of the 3rd Guards Infantry Division, supported by several T-40 tanks from the 122nd Tank Brigade. Armed with machineguns, they proved powerless against the even relatively lightly armoured vehicles from Bekker's battery. The 122nd Tank Brigade lost 2 tanks that day. It's worth mentioning that the battles were very fierce and the German march to Volkhov was anything but a walk in the park. The platoon went through several commanders during that time and one SPG was heavily damaged by a mine.

In the end, the 54th Army managed to stop the Germans at the outskirts of Volkhov and push them back to their initial positions in December. Over more than a month, 15th battery managed to fire off up to 1300 shells, or over 200 per gun. The evaluation of the vehicle in combat was very positive. t was very stable when firing and its off-road performance was good.

Use in combat, 1941

The combat history of the battery doesn't end there. In the winter and spring of 1942, elements of the 227th Infantry Division fought at Pogostye. Among them were SPGs from 15th battery. The SPGs also supported infantry from the 269th Infantry Division.

On February 16th, the battery deflected an offensive by the 54th Army. This was the first time the battery saw KV tanks from the 124th Tank Brigade. The Germans lost three vehicles in the ensuing battle. Turns out that armour piercing shells of the 105 mm guns were powerless against the thick armour of Soviet tanks.

The remaining SPGs fought for another month in the swamps and forests near Pogostye. They were quite handy in March. The armour improved the chances of survival of both the crew and the gun, and the 54th Army was poorly equipped when it came to AT guns. As a result, the SPGs frequently played a role reserved for "real" assault guns.

For example, they escorted German infantry that moved through forest roads. Their firepower was enough to destroy a machinegun nest of fight off an unexpected attack. According to German sources, 15th battery managed to shoot up a Soviet infantry column. This fact cannot be confirmed by Soviet sources, but in the chaos of forest battle, something like this could very well have happened.

The SPGs were also useful when it was time to break out from an encirclement. After the fierce battles of March, the battery had only two functional vehicles left.

Despite all attempts to repair the SPGs, 15th battery still had only two vehicles by the time the Volkhov Front began their Sinyavino Offensive. These SPGs fought in the First Battle of Ladoga.

One of the remaining SPGs was used to punch a corridor through to the semi-encircled 366th regiment commanded by M. Wengler. It was shot up by Soviet AT riflemen on a forest road. The second SPG was sent to cover one of the main supply routes when it was threatened by the 4th Guards Infantry Corps. Here, the vehicle was lost to tankers of the 98th Tank Brigade.

After battles in the swamps of Sinyavino, 15th battery had no vehicle left. Nevertheless, the battery remained in records of the 227th Infantry Division during Operation Spark. However, no more combat action by its SPGs can be found in documents.

The battlefields around Leningrad proved to be a tough trial for this unusual vehicle. Its design was well thought out and earned few complaints. Experience earned during its use came in handy when the Germans designed other SPGs.

Friday, 22 April 2016

Having broken the resistance of the German divisions, the Allies reached the Rhine by February-March of 1945. This river could reach 500 meters in width and was the last serious barrier before the industrial regions of Germany and its capital, Berlin.

The objective of the 21st Army Group commanded by the British Field Marshal Montgomery was to encircle the Ruhr industrial area from the north. The commander concentrated over 700,000 men, over 5000 tanks and SPGs, over 4000 guns, and enormous amounts of fuel, ammunition, and other equipment on the western shore of the Rhine. The Allies had more than a tenfold advantage over the Germans in every respect, but Montgomery did not expect a walk in the park. The German army was a deadly wounded beast.

First Assault on Binnen
On the night from March 24th to 25th, after a powerful artillery barrage and series of bomb strikes, Montgomery gave the order to cross the Rhine. The Allies had plenty of boats and were well covered by artillery, so even the advance units crossed with minimal losses. The crossing was illuminated by special projectors set up on the west shore of the river and tanks with special lights. Bridgelayer tanks followed APCs full of infantry, which helped amphibious Sherman Duplex Drive tanks to climb on shore. Having captured several large footholds, the Allies began building bridges and cleaning up the remainder of the German resistance.

In the 1st Canadian Army sector, infantrymen of the 9th brigade and soldiers from the highland regiments came ashore: Highland Light Infantry, Stormont, Dundas and Glengarry Highlanders, North Nova Scotia Highlanders, and the 7th Argyle Highlanders Regiment. A German stronghold in Binnen was in their way, defended by elements the 16th Fallschirmjager and 115th Panzergrenadier regiments, 600 troops in all with several AT guns, mortars, and StuG III SPGs are mobile reserves. The Canadians that assaulted the village numbered 800.

As the infantry drew closer to the village, the Germans recovered from the artillery strike. Resistance started to build up. By the morning of March 25th, the soldiers from the 7th regiment occupied several buildings near the village, but did not enter Binnen proper, covering the right flank of their neighbouring regiment.

The first attack on Binnen began on March 25th at 6:40 AM. The Canadian infantry was supported by Shermans from the Staffordshire Yeomanry regiments and 25-pdr (87.6 mm) howitzers. The Canadians that atacked from the south came under firs from machineguns, mortars, and hidden AT guns. Two tanks were knocked out. The Canadians managed to reach the closest embankment, climb up, and capture the German trenches, but they were suppressed by machinegun fire and could not advance to the village. The soldiers on the embankment had perfect positions to correct their artillery, but it would not fire: they were some 100 meters from highlanders that broke through and didn't want to risk friendly fire.

Two StuGs opened fire from the eastern side of the village. Three Shermans rushed to help. The lost this duel: one tank was knocked out, one bogged down, and the crew of the third fled. Lieutenant Colonel Forbes evaluated this frontal attack as unsatisfactory and ordered his soldiers to fall back.

From Two Sides
Forbes planned his next attack. Engineering teams would create a smokescreen to prevent German artillery and machineguns from aiming. The same units would attack under the cover of the smoke. Aside from the frontal attack, Forbes decided to attack Binnen from the left flank, using fresh forces. In order to make this possible, two platoons of highlanders (about 40 men) were sent to capture nearby Gritterbusch. The flanking groups would then clear the village from Germans.

In order to hide their presence, the soldiers gathered at the embankment. However, German mortar crews spotted this rotation and opened fire. The biggest danger to the attackers were German soldiers, hiding in the trenches with machineguns and grenade launchers.

Private J. Cameron performed an act of heroism. He came close to the enemy trench and threw in two grenades, killing four Germans. On the way back to his positions, he was shot in the back.

While the battle on the flank raged on, the rest of the forces gathered behind the smokescreen. With help from Wasp flamethrower carriers, they captured several buildings on the outskirts of Binnen. The Wasps could spit flame over 50 meters, killing Germans hiding in buildings or trenches. Thanks to their armour, the highlanders managed to deal with machinegun nests in two stone three-storey houses.

In the village, the Canadians were bogged down in urban combat against the Germans, who were set up in every house. Step by step, the highlanders were moving towards the center of Binnen, clearing out pockets of resistance, but taking heavy losses. Over 100 Germans were taken prisoner.

Counterattack and Capture
The commander of the German grenadiers decided to attack, ordering three SPGs and 150 infantrymen into battle. The counterattack began in the evening of March 25th around 7:00, starting at the Emmerich settlement. The grenadiers and StuGs were supported by artillery.

At first, the Germans managed to buckle the highlanders and destroy some vehicles. One Wasp was destroyed by a StuG, another by grenadiers. Then, the StuGs engaged the Shermans. The battle was at a short range, only 40 meters. Two Canadian tanks fired first, but their shells went too high. The experienced German crews calmly shot up the unlucky Shermans. Five Archer tank destroyers armed with powerful 17-pdr (76 mm) guns came to their aid.

A duel between German and Canadian SPGs began. One of the Archer commanders recalled: "The German tank was driving right at us, and could fire at any moment. I yell to my gunner: "Fire!" The first shot hit the gun mantlet and the SPG was engulfed in smoke." The second StuG was also knocked out, but likely by artillery called up from the opposite shore of the Rhine.

The Allies often used a fire control method called "time on target". This technique gathered fire from all batteries in the vicinities and, if possible, aircraft. This time, several dozen guns rained fire on the German defenders, including powerful 180 mm ones. Over seven minutes, Canadian artillerymen fired over 1400 rounds.

The artillery barrage suppressed the German counterattack and helped the Canadians fortify their new positions. Binnen was finally cleared in the middle of March 26th. The highlanders, aided by tanks and flamethrowers, cleared out the last of the German resistance, mostly snipers and machinegunners.

The Canadians lost 44 men dead and 68 wounded in the battle. The German losses were much higher: 230 dead and 200 captured, most of which were wounded by shrapnel or fire. The tank count was not in the Canadians' favour. Having destroyed two StuGs, they permanently lost five Shermans and two Wasps. Another few tanks and one Archer were repaired.

The fall of Binnen helped grow the Allied foothold by 48 km in width and 35 km in depth, and to later move into the heart of Germany. The Ruhr pocket soon formed, one of the largest encirclements of the Western front. After its surrender on April 18th, 1945, there was little resistance left in the path of the Allies. All possible German forces were trying to hold off the Red Army's rush for Berlin.

Even though KV tanks (and not just KV tanks) came with P-40 7.62 mm AA machinegun mounts, it took until October of 1944 for the IS series to get the same luxury, but at least it came with a caliber upgrade.

Aside from the DShK mount, this photo also gives you a good view of the folded up MK-4 periscope used in many Soviet tanks.

Wednesday, 20 April 2016

Stereotypically, Soviet tanks drive into battle plastered with red stars, the more the merrier. Realistically, the system of identification markings was a little bit more complicated. For instance, here's an order that's sure to excite any scale modeler with the variety of options it provides:

Variant

Infantry, artillery, cavalry, and other units

Tank and mechanized units

1

Day: an angle made from white material, corner towards enemy.

Night: yellow flare in the direction of the enemy.

Day: white circle on the turret or cabin, 26 cm in radius.

Night: yellow flare.

2

Day: Arrow made from white material towards enemy.

Night: green flare towards enemy.

Day: white square on the turret or cabin with 60 cm sides.

Night: green flare towards the enemy.

3

Day: letter Пmade from white material, top towards the enemy.

Night: red flare towards the enemy.

Day: white equilateral triangle with 60 cm sides on the turret or
cabin.

Night: red flare towards the enemy.

4

Day: letter T made from white material, top towards the enemy.

Night: green flare towards the enemy.

Day: white rectangle, 40 cm by 60 cm, on the turret or cabin.

Night: green flare towards the enemy.

Variant #1 is active on September 2nd, 3rd, 12th, and 13th.
Variant #2 is active on September 4th, 5th, 10th, and 11th.
Variant #3 is active on September 6th, 7th, 14th, and 15th.
Variant #4 is active on August 31st, September 1st, 8th and 9th.

Tuesday, 19 April 2016

"Comments on the draft of tactical-technical specifications of the SPG

1. The weight of 55 tons specified in the tactical-technical characteristics combined with the requested armour is impossible to achieve for the following reasons:

According to the tactical-technical requirements, the SPG will use the transmission and suspension of the KV. The weight of these components is 17,400 kg (including the engine, fuel system and cooling system), and cannot be reduced further.

The Br-2 system used in the SPG weighs 17,600 kg with the mount and ammunition.

If the mass of the SPG is limited at 55,000 kg, then the mass of the hull and the (immobile) turret will be 17,000 kg.

Due to the size of the system, the following dimensions have to be maintained:

Length: 7900 mm

Width: 1920 mm

Height (from bottom): 2570 mm

Building a hull that weighs 17,000 kg with these dimensions is impossible. Reducing the size is also impossible.

As an example, take the SMK-1 hull that had the following armour: 60 mm (sides, front, turret) 20-30 mm floor and 30 mm roof weighed 31 tons (including turrets). The requirements for the SPG are:

Front: 75 mm

Sides: 60 mm

Turret: 60 mm

Roof: 30 mm

Floor: 40-30 mm

It is not possible to design a 55 ton SPG with a turret and hull weighing 17 tons. During the design process, we used the following armour thicknesses:

Sides: 60 mm

Front: 60 mm (at 30 degrees)

Lower front: 50 mm (at 45 degrees)

Lower rear: 50 mm

Turret: 60 mm (at 10 degrees)

Floor: 30 mm front, 20 mm rear

Roof: 20 mm

Without fuel, ammunition and crew, the weight of this design is 60 tons. The combat weight is 65 tons. At 65 tons, the ground pressure (without sinking) is 0.83 kg/cm^2.

2.

The speed of aiming has been reduced by 33% vertically and 10% horizontally compared to the Br-2 field gun. The effort required to turn the elevation flywheel is up to 10 kg and the effort required for the horizontal flywheel is up to 8 kg.

With the current return mechanisms, you cannot fire at an angle of over 30 degrees.

The horizontal traverse is 4 degrees to each side, same as the field gun.

The ammunition capacity is 47 shells. There is no loading crane, only a loading tray like on the M-10 system in the KV.

The SPG fits into the "O" railway dimensions and is approaching the limits of the "O" dimensions.

Monday, 18 April 2016

"Summary of work on production and improvements of experimental prototypes of the Kirov factory heavy tank (Object #701)

On their own initiative, the Kirov factory has been working on a new heavy tank since the middle of 1943 (Object #701).

On April 6th, 1944, letter #5-1881s was sent to comrade Stalin, signed by comrades Beria, Malyshev, and Fedorenko with a request to approve the attached project of a GOKO decree, allowing the Kirov factory to begin building experimental prototypes of the new tank.

On April 8th, 1944, GOKO decree #5583ss was issued, allowing the NKTP to produce two experimental heavy tanks in April and perform trials with GBTU.

The Kirov factory produced the tanks and presented them for trials.

From June 28th, 1944 to July 30th, 1944, the Commission appointed by order #368/01 of the NKTP and Commander of the Armoured and Motorized Forces issued on June 3rd, 1944, began trials of the two experimental prototypes of object #701 (Lieutenant-General of the Tank Forces comrade Vershinin's Commission).

Trials showed that a series of components (final drive, gearbox) need improvements.

In his order #500s issued on August 11th, 1944, the People's Commissar of Tank Production comrade Malyshev instructed the Kirov factory to introduce improvements to the experimental prorotypes in accordance with the comments made by the commission and present the prototypes for secondary trials.

The results of the trials were reported to comrade Beria in letter #5-4513s signed by comrades Malyshev and Fedorenko on August 11th, 1944.

The Kirov factory improved the experimental prototypes and sent them for secondary trials.

Secondary trials were held at the NIBT proving grounds from December 17th, 1944, to January 24th, 1945. The commission appointed by the Commander of Armoured and Motorized Forces recommended the tank for adoption by the Red Army.

On February 8th, 1945, the Chair of the Commission, Engineer-Colonel comrade Blagonravov, reported the results of the trials to the Armoured and Mechanized Forces Council.

The Council decreed that:

Report to the Government regarding the adoption of the new heavy tank (Object #701) into the Red Army and organization of its production at the Kirov factory as a part of the main tank and SPG production program.

Approve the report of the Commission regarding the experimental prototypes.(Excerpt from the minutes of meeting #4 of the Armoured and Mechanized Forces Council on February 8th, 1945)

On February 11th, 1945, letter #836878 by the Armoured and Mechanized Forces Council reported to comrade Beria of the trials and asked for his approval regarding accepting the new tank into service.

Due to the fact that the People's Commissar of Tank Production, comrade Malyshev, insisted that the tank should be tested in difficult road conditions, a letter was written in March of this year to comrade Beria signed by comrades Malyshev, Korobkov, Biryukov, and Zaltsmann with a proposal to perform additional trials of Object #701 and simultaneously allow the Kirov factory to begin preparing for production of the new tank.

According to order #135/0029 of the NKTP and Commander of the Armoured and Motorized Forces issued on March 22nd, 1945, the supplementary trials of Object #701 were conducted. One prototype that previously travelled 1451 km was tested at the NIBT proving grounds over an additional 307 km. The second prototype was being tested in Chelyabinsk and travelled 686 km. Trials were conducted off-road in conditions of spring mud.

Results of the additional trials were sent in memo #1658 dated May 5th, 1945 from the Chief of the Tank Directorate to the Deputy Commander of the Armoured and Mechanized Forces, Colonel-General of the Tank Forces, comrade Korobkov.

Currently, the prototype of the new heavy tank with a new turret with thicker armour and a coaxial DShK machinegun is located at the NIBT proving grounds."

Sunday, 17 April 2016

At the start of the Great Patriotic War, Soviet military intelligence and the GAU had a very approximate idea about the types and characteristics of German tanks. This deficiency led to an overestimation of the possibilities of German armour and the launch of the KV-3, 4, and 5 programs in March of 1941. Even information on real German tanks was sparse. Intelligence missed the increase of the front armour of PzIII and PzIV tanks to 50 mm and use of 50 mm guns. This lack of information had to be made up for in the most reliable way during the war: studying trophies. Among the vehicles that were glossed over by Soviet intelligence was the StuG assault gun.

Present from Kiev
The first use of this vehicle, envisioned by Field Marshall Manstein, was in France, in May-June of 1940. It would be incorrect so say that Soviet intelligence learned nothing about the StuG. However, it did not earn much attention, and its description was brief.

"As a rule, assault gun squadrons accompany infantry in attacks of fortified positions and strongholds in the direction of the main attack, first in motorized divisions, then later in tank and infantry divisions. The squadrons are armed with 75 mm tank guns installed on the chassis of the PzIII medium tank with a special turret and armour. The main task for these vehicles is the destruction of the enemy with direct fire."

The Soviet military had no idea about the importance and effectiveness of these low, mobile, and well armed fighting machines. Meanwhile, in June of 1941, more than 10 StuG battalions (Sturmgeschütz-Abteilung, or StuG.Abt.) assembled on the Soviet border. Among them was 197th StuG. Abt. under the command of Major Helmuth Christ.

This battalion was formed in October of 1940 and was armed with StuG Ausf. B vehicles. StuG. Abt. 197 had its baptism by fire alongside the 132nd Infantry Division in May of 1941 during the invasion of Yugoslavia. During the start of the invasion of the USSR, the battalion was subordinate to

XXXXVIII Tank Corps of Army Group Center. Soon after the fighting began, it was transferred to XXXXIV Corps in Army Group South.

That same vehicle at the NIIBT Proving Grounds, early September of 1941. The damage to the suspension and the letter E on the side can be clearly seen.

On August 15th, the battalion was located at the city of Kanev, where fierce battles for the Dnieper were fought. Soviet infantry counterattacks managed to capture at least two StuG III Ausf. B from StuG. Abt. 197. The vehicles from 3rd battery was captured intact and was used in a photoshoot with the soldiers who captured it. The second vehicle, #90247 with the name Prinz Eugen, was also mobile. According to StuG. Abt. 197 records, both vehicles were lost after hitting mines. After brief repairs, they were transferred to the Soviet rear.

The assertion that at least one of the vehicles went to fight with a Soviet crew is often made, but this is not true. In early September, the vehicles from 3rd battery was already at the NIIBT Proving Grounds. As for Prinz Eugen, it was transferred to the rear of the Central Front. A brief description was composed, with the trophy getting the name "medium German tank T-3 with an immobile turret". The description included external and internal characteristics of the vehicle. These characteristics were fairly close to the real ones. Despite the urgency, the specialists who studied the vehicle had time to partially take it apart and put it back together.

The second captured StuG III Ausf. B from StuG. Abt. 197.

The NIIBT Proving Grounds went in a different direction. Instead of beginning a detailed study, they made a brief composition of its characteristics. A summary of German armour was ready by September 11th, 1941. The tactical-technical characteristics in this summary were more precise, especially when it came to armour thickness. Aside from measurements, a brief trials were also staged, where the StuG reached a speed of 50 kph.

That same vehicle from the left. This StuG had the personal name "Prinz Eugen".

In NIIBT documents, the StuG was referred to as "artillery tank" or "Artsturm" for short. It's not known who invented this term, but it stuck to the StuG in Soviet documents.

Tough Nut

The StuG III was studied to compose a guidebook on German vehicles that was so desperately needed at the front. Because of this, trials were performed in an accelerated way, and some conclusions may be unfounded.

StuG III from the rear.

"The artillery assault tank is designed to act in the first echelon of tanks. The tank has no turret. It can only fire forward in a 28 degree arc by turning the gun on a mount. There are no machineguns. The lower part of the artillery tank, the suspension, the engine, the planetary turning mechanism, and the controls are taken from the PzIII. The gearbox is the same as the one on the PzII Ausf. B and only differs in its size.

The armour of the tank can be defeated by guns of all calibers. It is possible to destroy the tank through the opening above the gun mount using a bottle of incendiary fluid or a grenade."

The conclusions regarding protection seems hasty. Of course, there were some poor decisions made regarding the vehicle, and the protection of the casemate was one of them. The gun sight opening "caught" shells, but it was changed in the Ausf. C version. The gun mount was also far from ideal as far as shell resistance went. However, the protection offered by the front armour went underappreciated by the proving grounds. The StuG III was the first mass produced German vehicle with anti-shell armour. The front armour of even the StuG III Ausf. A was 50 mm. The vehicle was reliably protected from the 37 mm gun. The PzIII and PzIV only received improved armour a year later.

Poster with vulnerable parts of the StuG, which slightly differed in reality.

It was already obvious that the 45 mm gun will have problems with German armour in late 1940. A 30 mm thick evacuation hatch from a PzIII tank bought in Germany was fired upon, penetrated, and even shattered, but not on the first try. These results showed that thicker armour would be impenetrable. Nevertheless, in September of 1941, the verdict was "vulnerable to artillery of all calibers". The same verdict was repeated in the flyer from the "Destroy German Tanks" series.

A full fledged study of the vehicle's armour was only made in September of 1942. PzIII, PzIV, Pz38(t) and the StuG were tested at the NIIBT Proving Grounds at Kubinka and their Kazan branch. The tanks were fired upon by Soviet, American, British, German, Czechoslovak, and French tank guns. Their resistance at 50, 100, 200, 400, 600, and 800 meters was measured.

Results of firing the 45 mm gun (1 and 2).

First, the vehicle was fired upon by the 45 mm mod. 1942 tank gun in the T-70 tank. It penetrated the 30 mm armour with no problems from a range of 850 meters. Firing at the front was a different story. From 100, then 50 meters, the result was the same: 20 mm dent. The shells fell apart on impact.

Hits from 2-pdr shells. The penetration was likely by chance.

The story can end here with the conclusion that Soviet armament was bad, but similar results were shown by another gun: the British 2-pdr (40 mm) in a Canadian Valentine VII tank. The sides also proved effortless. As for the front armour, it was only penetrated once, and the penetration was deemed unsatisfactory, since the shell landed into the joint between the central and lower front plates. In all other cases, the shells made 25 mm deep dents. One can only feel sorry for British tankers whose main armament was the 2-pdr gun until the fall of 1942.

Penetrations by 37 mm subcaliber rounds from the A-7 gun on the Pz38(t)

A similar result was attained by the 37 mm A-7 gun on the Czechoslovak Pz38(t) tank. It could confidently penetrate the sides, but the front was invulnerable: the shells left 40 mm deep dents. The results were different for subcaliber shells: they could penetrate at 100, 200, and 400 meters.

The 37 mm M5 gun installed in the American light M3 tank performed better. Its M51 shell easily penetrated the front of the StuG at 100 meters, and 35-50 mm deep dents were formed at 150 meters. This can primarily be explained by the larger casing size used by Gladeon Barnes in its creation, giving the gun's shells a higher velocity compared to British and Soviet analogues.

The 47 mm SA 35 gun on the Somua S35 was even more effective. It could penetrate the front of the StuG III from 400 meters, but at this range only every other shot penetrated. The German 5 cm KwK 38 L/42, the stock armament on PzIII tanks by 1942, could penetrate the front of the StuG at 800 meters.

Penetrations left by the SA 35 gun installed in the French Somua S35 tank.

The 75 mm M2 gun used in the American M3 medium tank achieved curious results. The first Lend-Lease convoys didn't bring armour piercing ammunition, so HE was used. The results were poor, not a single penetration was made. The maximum that was achieved was a 10 mm dent. In addition, a deep dent was formed in the transmission cover while firing at the upper front plate. The 76 mm F-34 achieved different results and made Swiss cheese from the StuG at all distances. The armour caved in upon impact, forming many fragments.

Results of the 75 mm M2 gun used on the American M3 medium tank.

Landmark

At the same time, the StuG III was being studied at NII-48. The composition of the armour and joints between plates were being examined and successful design decisions that could be implemented in Soviet production were extracted.

"The hull of the German Artsturm tank:

The hull is welded. The ceiling of the fighting compartment is attached by bolts with a hidden head. Initially, the front plate was 50 mm thick, the sides were 30 mm thick, and the rear was 20 mm thick. Later, the rear 20 mm plates were replaced by 50 mm plates.

The hull is composed of rolled Chromium steel with 0.1% Vanadium. The Brinell hardness of the plates is 337-476, the diameter of the print is 2.8-3.32. The armour is malleable, has good resistance, and doesn't chip.

...

German PzIII, PzIV, and Artsturm tanks are made with Chromium steel and have good shell resistance. The composition of armour can be used to produce armour thicker than 50 mm. Curing, rolling, thermal conditioning and welding of Chromium steels mark 5140 and 5150 is already mastered by our industry and putting this armour into production will not be a problem.

A Chromium electrode containing 2.1% Chrome and 0.2% Carbon can be recommender."

Layout of the StuG's armour from NII-48's report.

It is worth mentioning that work on 45 mm subcaliber shells and a 45 mm gun with a lengthened barrel was going on before the trials of German tanks. The results of the trials only hurried both designs.

Initially, the German novelty was of no interest to Soviet designers. Later, the StuG III had a big effect on the development of medium self propelled artillery. Before, Soviet SPG designs were, as a rule, open topped tank destroyers with rotating turrets, like the U-20 project. By spring of 1942, the priorities shifted to assault guns with closed casemates, similar to the StuG III, but that is a topic for another article.